Twelve experimental studies are proposed. This research examines changes in adults' syntactic processing abilities and basic psycholinguistic processes. The general hypothesis is that elderly adults have an impairment of syntactic analysis as a result of reductions in working memory capacity or attentional deficits. An important focus of this research will be the assessment of individual differences in syntactic processes and the examination of changes in psycholinguistic performance over the course of this project. Additionally, this research will evaluate the effectiveness of guidelines for the preparation of prose materials for the elderly. The research is designed to assess changes in adult psycholinguistic abilities across the life-span. The general hpothesis to be tested in a series of experimental studies is that elderly adults suffer impairments of their ability to produce and understand complex sentences. Effective procedures for optimizing adults' performance by minimizing processing demands will be designed on the basis of the experimental studies. The specific goals are to a) identify age-related changes in adults' production and comprhension of complex sentences such as those ivolving left-branching relative clauses, gerunds, that-clauses, and wh-clauses; b) identify age-related changes in adults' production and comprehension of complex auxiliary verbs such as those indicating sentence modality and aspect; c) identify age-related changes in adults' running memory span for prose, processing of syntactic and semantic information, ability to infer anaphoric referents, and comprehension of discourse structures; d) identify stable patterns of individual performance on psycholinguistic tests that may be associated with differences in speaking style, education, intelligence, memory ability, or other psychosocial variables; e) identify effective guidelines for the preparation of prose materials to optimize adults' comprehension of complex sentences and auxiliary verbs.